32)Lincosamides. Amphenicols. Glycopeptides Flashcards
Lincosamides
A family of 8-C thin-galactoside antimicrobes
- Narrow spectrum of activity
- Bacteriostatic
- G+ bacteria - staphylococcus + Streptococcus
- Excellent activity against anaerobic bacteria
Mechanism of action
Prevent bacteria from replicating ⇢ binds to 50s subunit on ribosomes ⇢ Prevents protein synthesis
Classification
Clindamycin
- Used for: Middle ear
- bone/joint infections
- Pelvic inflammatory disease
- Strep throat
- Pneumonia
- Available orally, IV or topically
Lincomycin
- Rarely used due to toxicity
- Reserved for those w/penicillin allergies
- IM or IV
Pharmacokinetics
- Well absorbed following oral administration
- Widley distributed in tissues, bones + body fluids
- Metabolised in liver to inactive products
- Excreted mainly in bile
- Serum ½ life = 3hours
Adverse effects of clindamycin
diarrhoea
Superinfections ⇢ Pseudomembranous colitis
Neutropenia
Skin rashes
Impaired liver function
Amphenicols
- Phenylpropanoid structure
- Also bind to 50s subunit of ribosome ⇢ inhibit protein synthesis
- Bacteriostatic for MOs
- Bactericidal ⇢ H.influenzae + N. Meningitis
- Broad spec antibiotic
- Active against G+ cocci + G-ve bacteria + anaerobic bacteria ⇢ Clostridium, Rickettsia, Chlamydia + Mycoplasma
Classification
Chloramphenicol
- Treats conjunctivitis
- meningitis
- plague
- cholera
- typhoid IV
Thiamphenicol
Azidamphenicol
Reisstance
Production of acetyltransferase ⇢ inactivates chloramphenicol
Pharmacokinetics
- Chloramphenicol can be administered orally or IV
- Well distributed throughout body + CSF
- 60% bound to plasma proteins
- Crosses placenta + secreted in milk
- Converted in liver to highly water soluble monoglucuronide
- Excreted in urine
- Serum ½ life = 3 hours
Adverse effects of Chloramphenicol
Nausea, vomiting + diarrhoea
Superinfections ⇢ candidiasis
Anaemia, Leukopenia + Thrombocytopenia
Grey baby syndrome ⇢ in infants ⇢ cyanosis + cardiovascular collapse
Neonates deficient in hepatic glucuronyl transferase enzyme ⇢ responsible for chloramphenicol elimination
Drug interactions
Chloramphenicol ⇢ may inhibit cytochrome P450 mediated metabolism of:
- Phenytoin
- Oral hypoglycaemic agents
- Warfarin/indirect coagulants
Phenobarbital ⇢ ⇣ serum concs of chloramphenicol
Glycopeptides
Vancomycin ⇢ glycopeptide antibiotic
- Bactericidal ⇢ inhibits cell wall synthesis
- Used IV ⇢ MRSA infections
- Used orally ⇢ Pseudomembranous colitis
- Effective against G+ bacteria,
- Used in MRSA infections + when patient has hypersensitivity to penicillin
Classification
Vancomycin
Teicoplanin
Telavancin
Ramoplanin
Mechanism of action
Inhibits peptidoglycan synthesis ⇢ blocks construction of cell wall
Side effects
Hearing loss
Low BP
Bone marrow suppression
Tissue necrosis + phlebitis at injection site w/pain
Safety in pregnancy is unclear
